Effects of low-crude protein diets supplemented with arginine, glutamine, threonine, and methionine on regulating nutrient absorption, intestinal health, and growth performance of Eimeria-infected chickens

Eimeria of chickens: the changing face of an old foe

RESEARCH HIGHLIGHTS

The cost of coccidiosis in chickens fluctuates considerably, peaking in 2022.Three new Eimeria species can infect chickens and escape current vaccines.Eimeria infection exerts wide-ranging effects on enteric microbiota.

Effects of Amino Acid Supplementation on the Growth Performance of Broiler Chicks Challenged With Coccidiosis: A Meta-Analysis

This meta-analysis aimed to evaluate the effects of amino acid supplementation on the growth performance of broiler chicks challenged with coccidiosis. Data were collected on authorship, publication year, study sample characteristics and outcomes of interest related to growth performance. Effect sizes were calculated for both overall effects and the individual effects of each amino acid. The effects of moderator factors, such as supplementation levels and duration, were also assessed, and bias was calculated. Works were obtained from PubMed, Elsevier, ScienceDirect, Wiley, Springer Link and Scopus databases, with the help of search engines like Google Scholar and ResearchGate, covering the period from 2013 to 2023. A random-effects model was used. Thirteen works were included in the current analysis, examining the effects of arginine (n = 4), methionine (n = 6), threonine (n = 3) and glutamine (n = 3). Amino acid supplementation [0.326, CI 95% (0.297-0.355); p = 0.000], arginine [0.430, CI 95% (0.293-0.568); p = 0.000] and threonine [0.793, CI 95% (0.193-1.38); p = 0.009] significantly increased body weight. Amino acid supplementation [0.052, CI 95% (0.022-0.081); p = 0.000] and arginine [0.317, CI 95% (0.049-0.585); p = 0.000] also significantly increased feed intake. Higher levels of amino acids (≥1.50%) and longer supplementation periods (≥15 days) significantly increased body weight and feed intake, while reducing the feed conversion ratio. Funnel plots, fail-safe N and Egger tests showed no evidence of bias. In conclusion, arginine supplementation has the potential to increase body weight and feed intake in poultry challenged with coccidiosis. Higher doses of amino acids and longer supplementation periods are recommended in such cases.

Effects of graded yeast cell wall supplementation on growth performance, immunity and intestinal development of broiler chickens raised in floor pens for 42 days

This study was conducted to evaluate the effects of dietary supplementation of a novel soluble yeast cell wall (YCW) on growth performance, gut health, intestinal morphology, and immune response in broiler chickens for 42 days. A total of 480 one-day-old Cobb 500 male broilers were randomly assigned to four treatments with six replicates and each replicate of twenty broiler chickens: a control group (CON) without feed additive supplementation, and three groups supplemented with YCW at 0.025 % (YCW1), 0.050 % (YCW2), and 0.100 % (YCW3). Results showed that 0.025 % and 0.100 % YCW supplementation significantly increased (P < 0.05) final body weight (BW) and overall body weight gain (BWG) while reducing overall feed conversion ratio (FCR) compared to the CON group. The YCW supplementation also improved (P < 0.05) the balance of gut microbiota by increasing beneficial bacteria (Lactobacillus) and decreasing Salmonella, a potential foodborne pathogen in humans in the ceca. Although intestinal morphology was not significantly affected, YCW supplementation numerically increased the villus height: crypt depth ratio (VH:CD) compared to the CON group. Furthermore, YCW reduced the mRNA expression of pro-inflammatory cytokines (IL-1β and INF-γ) and tight junction protein claudin-1 (CLDN-1) (P < 0.05), suggesting balanced immune response and improved intestinal barrier function. In conclusion, the supplementation of soluble YCW in broiler diets positively influenced growth performance, gut microbiota composition, and immune response, demonstrating its potential as a viable alternative to antibiotics for improving broilers' health.

Phytase, 25-hydroxyvitamin D3 and cocci vaccination to broilers fed a calcium and phosphorus-reduced diet under Eimeria spp. challenge: effects on growth performance and intestinal health

A study evaluated the effects of phytase, 25-hydroxyvitamin D3 (25OHD), and cocci vaccination on broilers fed a diet reduced in calcium (Ca) and available phosphorus (avP) under Eimeria challenge. A total of 840 one-day-old male broilers were assigned to a 2 × 5 factorial arrangement based on cocci vaccination and dietary treatments. Half of the birds were vaccinated against coccidia on d 1, and all birds were orally challenged with Eimeria spp. (sporulated oocysts: 12,500 of E. maxima, 12,500 of E. tenella, and 62,500 of E. acervulina) on d 14. Dietary treatments included: 1) a nutrient adequate diet (PC); 2) a diet reduced by 0.2% in Ca and avP (NC); 3) NC plus 1,500 FTU/kg of phytase (NC+PHY); 4) NC plus 3,000 IU/kg of 25OHD (NC+25OHD); 5) NC with both PHY and 25OHD (NC+PHY+25OHD). SAS was used for data analysis, with significance set at P ≤ 0.05. Pre-infection growth performance was comparable across the treatments. However, vaccinated birds exhibited higher body weight (BW) and body weight gain (BWG) from 0 to 6 d postinoculation (DPI; P < 0.05). The NC diet reduced BWG from 6 to 12 DPI and increased the feed conversion ratio (FCR) during 6 to 12 DPI and the overall period (0-26 d) compared to the PC birds. In contrast, the supplementation with phytase, 25OHD, or both, returned BWG and FCR to levels seen with the PC diet (P < 0.01). Vaccinated birds also had reduced gut permeability at 5 DPI, increased intestinal villus height, and lower expression levels of the tight junction proteins junctional adhesion molecule 2 (JAM2) and occludin (OCLN) at 6 DPI (P < 0.05). Interestingly, the cocci vaccine resulted in lower E. acervulina but higher E. tenella oocyst shedding at 6 DPI (P < 0.01). Interaction effects were observed for duodenal lesion scores and ileal crypt depth at 6 DPI (P < 0.05). In conclusion, coccidial vaccination improved growth performance, decreased intestinal permeability, enhanced intestinal morphology, and modulated tight junction protein gene expression under Eimeria infection. Reducing dietary Ca and avP levels adversely affected growth performance and FI during the recovery phase, but these negative effects could be mitigated by supplementing with phytase or 25OHD.

Effects of phytase and 25-Hydroxycholecalciferol supplementation in broilers fed calcium-phosphorous deficient diets, with or without Eimeria challenge, on growth performance, body composition, bone development, and gut health

The study evaluated the effects of nutritional strategies on broilers challenged with Eimeria from d 14 to 26. A total of 840 Cobb male broilers were fed five diets in a 2 × 5 factorial arrangement: 1) nutrient adequate diet (PC; 0.84% calcium [Ca], 0.42% available phosphorus [avP]); 2) Ca-P deficient diet (NC; 0.64% Ca, 0.22% avP); 3) NC + 1500 FTU/kg phytase of diet (NC + PHY); 4) NC + 5000 IU/kg 25-Hydroxycholecalciferol of diet (NC + 25OHD); and 5) NC with both supplements (NC + PHY + 25OHD), with and without Eimeria challenge. All treatments had six replicate cages with 14 birds per cage. At 5 days post inoculation (DPI), the challenged birds exhibited higher serum fluorescein isothiocyanate-d (FITC-d) levels than the unchallenged birds (P < 0.001). The NC + PHY and NC + PHY + 25OHD groups exhibited lower FITC-d levels compared to the NC + 25OHD group (P = 0.012). Significant interaction effects between Eimeria challenge and dietary treatments were observed on various parameters. During 0 to 6 and 0 to 12 DPI, Eimeria challenge resulted in decreased the body weight gain (BWG) (P < 0.05) but had a negative effect on the feed conversion ratio (FCR) in birds compared to the unchallenged group (P < 0.05). Reducing Ca and avP levels in the diet (NC) did not adversely affect BWG, but negatively impacted FCR, bone ash weight, ash concentration, and femur bone microstructure parameters (P < 0.05). On 12 DPI, Eimeria challenge led to decreased tibia bone weight, bone volume, fat-free bone weight (FFBW), and ash weight of birds (P < 0.05). Supplementation with phytase alone or in combination with 25OHD improved growth performance, gut permeability, bone ash and bone microstructure parameters in birds (P < 0.05). However, the group fed 25OHD alone showed enhancements on growth performance, mineral apposition rate (MAR), bone ash concentration and ash percentage of the birds (P < 0.05). In conclusion, lowering Ca and avP levels in the diet negatively affected FCR and bone development but did not affect intestinal integrity in broilers. Dietary supplementation of phytase, 25OHD, or phytase in combination of 25OHD could enhance the growth performance and bone quality of broilers infected with Eimeria. Notably, the benefits of phytase supplementation were generally more pronounced than those associated with 25OHD supplementation; however, the combination of phytase and 25OHD could induce optimum effects.

Growth performance and immune response of broilers during active Eimeria infection are modified by dietary inclusion of canola meal or corn-DDGS in reduced-protein corn-soybean meal diets

The objective of this experiment was to study the effects of partial replacement of soybean meal (SBM) with canola meal (CM) or corn-distillers' dried grains with solubles (cDDGS) in reduced-protein (RP) diets for Eimeria-infected broilers. A total of 1120 broiler chicks were distributed in a 4 × 2 (4 diets × with or without infection) factorial arrangement with 7 replicates per treatment and 20 birds per replicate. The 4 diets, fed between d 7 and 42, were (i) a standard diet with crude protein at 200 g/kg (SP); (ii) a RP (crude protein at 160 g/kg) corn-SBM diet (RP-SBM); (iii) a RP diet in which 80 g/kg CM replaced 60 g/kg SBM (RP-CM); and (iv) a RP diet in which 100 g/kg cDDGS replaced 50 g/kg SBM (RP-cDDGS). On d 15, birds were infected with mixed Eimeria (+E) oocysts. Birds and feed were weighed at intervals for growth performance, and samples for immunology responses were collected on d 21. The results showed as follows: 1) during the acute infection phase, diet × Eimeria infection was shown by the diets having no effect in the uninfected group. In contrast, the RP-SBM diet tended to produce higher (P < 0.10) weight gain among the infected birds. The d 42 body weight was greater (P = 0.001) for the uninfected birds. 2) There was a significant diet × Eimeria infection on bile anti-Eimeria immunoglobulin A (IgA) concentrations (P = 0.015), splenocyte proliferation, macrophage nitric oxide (NO) production (P < 0.001), and cecal tonsil interleukin (IL)-17 mRNA amounts (P < 0.001). Most of these responses were not influenced by the diets in the uninfected birds. However, among the infected birds, birds fed RP-SBM had higher (P < 0.05) bile IgA than those fed SP or RP-cDDGS. For the spleen, the interaction was that birds fed RP-SBM or RP-cDDGS diets had the highest or lowest NO production, respectively, and birds that received RP-SBM had greater (P < 0.05) splenic CD8+:CD4+ cell ratio than other diets. In conclusion, partial replacement of SBM with CM or cDDGS had only a marginal effect on d 42 body weight and FCR of the broiler chickens receiving the RP diets. In contrast, these had a negative impact on the immune responses of the broiler chickens.

Synergistic impact of Salmonella typhimurium and Eimeria spp. coinfection on turkey poults: Growth performance, salmonella colonization, and ceca microbiota insights

Salmonella contamination in poultry products is a significant concern due to its potential to cause severe economic losses and public health problems. On the other side, coccidiosis is induced by Eimeria (E.) species. involves the destruction of host intestinal epithelial cells and subsequent invasion of pathogens, resulting in performance reduction and enhanced pathogen infection in poultry and economic losses for the poultry industry. A study was conducted to evaluate the impact of Eimeria infection and Salmonella typhimurium (ST) on growth performance, Salmonella colonization, and ceca microbiota in turkey poult. A total of 420 one-day-old male turkey poults were randomly allocated into six treatments, with five replicated cages for each treatment, over a 21-day experimental period. The study followed a 2 × 3 factorial design. Treatments consisted of NC, negative control without any challenge; T1, challenged with 8000 oocysts of E. meleagrimitis and E. adenoeides at d 8; T2, challenged with 16,000 oocysts of E. meleagrimitis and E. adenoeides at d 8; T3, challenged with nalidixic acid-resistant Salmonella typhimurium (ST) at d 0; T4, challenged with ST at d 0 and 8000 oocysts of E. meleagrimitis and E. adenoeides at d 8; T5, challenged with ST at d 0 and 16,000 oocysts of E. meleagrimitis and E. adenoeides at d 8. The Eimeria challenge groups significantly reduced the BW compared to the non-challenge group (P < 0.001). The challenged groups decreased FI during 9-14 days of age (P < 0.01). Salmonella typhimurium did not affect BW entire trial period (P > 0.05). Gut permeability (GP) increased in the challenge groups compared to the NC group (P < 0.001). Both ST and Eimeria significantly decreased superoxide dismutase (SOD) in the liver (P < 0.01). The challenge groups had lower villus height (VH) and higher crypt depth (CD) compared to the NC group, resulting in decreased VH:CD ratio in the duodenum and jejunum (P < 0.01). The groups T1, T2, and T4 had significantly higher fat deposition than the NC group (P < 0.05). The coinfected groups (T4 and T5) had higher salmonella colonization in the spleen compared to the ST-infected group (T3, P < 0.05). The ST challenge significantly decreased alpha diversity, including pielou evenness and Shannon entropy (P < 0.05). The Proteobacteria phylum and Enterobacteriaceae family significantly increased in T5 compared to the NC, T1, T2, and T3 (P < 0.05). In conclusion, Eimeria infection negatively impacted growth, gut health, intestine barrier integrity, and histology, while Salmonella had a milder effect on performance. Coinfection with Salmonella and Eimeria spp. led to changes in gut microbiota and increased liver Salmonella colonization and fat deposition in turkey poults.

Effects of deoxynivalenol contaminated corn distiller's dried grains with solubles on growth performance, body composition, immunological response, and gastrointestinal health in young pullets

Mycotoxins, particularly deoxynivalenol (DON), are common contaminants in feed ingredients such as corn distiller's dried grains with solubles (DDGS) and pose significant risks to poultry health. This study investigated the effects of feeding naturally DON contaminated DDGS on growth performance, body composition, immunological response, and gastrointestinal health in young pullets. A total of 360, 4-week-old Hy-Line W36 pullets were randomly assigned to diets with increasing levels of naturally DON contaminated DDGS (0, 5, 10, 15, and 20%) over 28 days, resulting in dietary DON concentrations ranging from below the limit of quantification to 15.4 ppm. Diets with DON concentration exceeding 8.9 ppm, corresponding to 15% and 20% DDGS inclusion, resulted in significantly lower body weight gain (BWG) and feed intake (FI) from experimental day 14 to day 28 compared to DON concentration below 5.9 ppm (0, 5 and 10% DDGS groups; P = 0.024 and P = 0.007, respectively). Body composition analysis showed a higher tissue fat percentage in the 20% DDGS group (15.4 ppm DON) by day 28 compared to lower inclusion levels (P = 0.021). Immunologically, a significant increase in the CD4+:CD8+ ratio in spleen was observed in the 20% DDGS group compared to the 0% DDGS group (P = 0.013), whereas both 15 and 20% DDGS inclusion levels significantly increased the ratio in cecal tonsil (P < 0.001). Additionally, interleukin 1β (IL-1β) expression significantly increased in the cecal tonsil by day 28 with 15 and 20% DDGS inclusions (P = 0.002). Gut health was compromised as gut permeability increased linearly with increasing DDGS inclusion (linear, P = 0.043), aligning with significant alterations in the expression of the tight junction protein occludin (OCLN; P = 0.007). Antioxidant responses in the liver showed increased superoxide dismutase (SOD) activity in early exposure (day 13, P = 0.038), followed by decreased SOD activity (P = 0.001) and reduced glutathione (GSH) levels (P < 0.001) by day 28. In conclusion, feeding DON-contaminated DDGS at higher inclusion levels (15% and 20%) with final diet DON concentrations exceeding 8.9 ppm over 28 days adversely affects growth performance, immune function, and gut integrity in young pullets.

Alterations in the gut microbiota of Eimeria infected broiler chickens fed diets supplemented with varying levels of dietary calcium and phosphorus, along with 25-hydroxycholecalciferol

The purpose of the study was to investigate the effects of the reduced dietary calcium (Ca) and phosphorus (P) level and supplementation of 25-hydroxycholecalciferol (25-OHD3) on the expression of vitamin D receptor (VDR) and antimicrobial peptides and gut microbiota of broiler chickens with/without Eimeria challenge. A total of 576 fourteen-day-old broiler chicks were randomly allocated according to a 2 × 2 × 2 factorial design with main effects including Eimeria challenging (125,000 Eimeria acervulina, 25,000 Eimeria maxima, and 25,000 Eimeria tenella), dietary Ca and P levels (0.84% Ca and 0.42% available P or 0.64% Ca and 0.22% available P), and supplementation of 25-OHD3 (3,000 IU/kg) of 6 replicates. Three-way ANOVA was performed, and the effects of 3 main factors and their interactions were investigated. The reduced dietary Ca and P level downregulated cathelicidins 3 (CATH3) in the upper jejunum in the Eimeria challenging condition (interaction; P < 0.05). The reduced dietary Ca and P level decreased the relative mRNA expression of jejunal avian beta defensin 5 (AvBD5) in the Eimeria challenging condition (interaction; P < 0.05). The reduced dietary Ca and P level tended to decrease the relative mRNA expression of jejunal AvBD9 in the Eimeria challenging condition (interaction; P = 0.051). The reduced dietary Ca and P level decreased observed features (alpha diversity parameter for richness) in the upper jejunal microbiota in the Eimeria challenging condition (interaction; P < 0.05). The supplementation of 25-OHD3 decreased the relative abundance of the phylum Bacteroidetes (P < 0.05) and increased the relative abundance of the family Ruminococcaceae (P < 0.05) in the cecal digesta. The supplementation of 25-OHD3 decreased the serum endotoxin level in the Eimeria challenging condition (interaction; P < 0.05). Therefore, the reduced dietary Ca and P level modulated the upper jejunal microbiota via modulating the expression of antimicrobial peptides, and the supplementation of 25-OHD3 favorably modulated the cecal microbiota in broiler chickens with/without Eimeria challenge.

Dietary advanced chelate technology-based 7-mineral supplement improves growth performance and intestinal health indicators during a mixed Eimeria challenge in broiler chickens

The health and productivity of broilers may be improved by optimizing the availability and levels of trace minerals (TM) in their feed, especially in the presence of parasites. This study investigated the effects of replacing inorganic TM (ITM) with an advanced chelate technology-based 7 TM (ACTM) on performance, hematology, lesion score, oocyst shedding, gut morphology, and tight junction structure in broilers challenged with mixed Eimeria species. There were 480 1-day-old broiler chickens divided into 5 groups: uninfected negative control and recommended levels of ITM (NC); infected positive control and recommended levels of ITM (PC); or PC supplemented with salinomycin (SAL); PC diet with 50 % ACTM instead of ITM (ACTM50); or PC diet with 100 % ACTM instead of ITM (ACTM100). All groups, except NC, were orally challenged with mixed Eimeria spp. oocysts on day 14. Each group had 6 replicate cages, with 16 birds per replicate. The results showed that the NC, SAL, and ACTM100 groups had higher (P < 0.05) body weight, average daily gain (ADG), and European production efficiency index (EPEI), as well as a lower (P < 0.05) feed conversion, mortality rate, and heterophile to lymphocyte ratio compared to the PC group, with the NC group having the highest ADG and EPEI throughout the experiment. The SAL and ACTM100 groups had lower (P < 0.05) intestinal lesion scores and oocyst numbers compared to the PC group, although all coccidiosis-challenged groups had higher oocyst shedding compared to the NC group. On day 24, the challenged birds in the SAL and ACTM100 groups had higher (P < 0.05) villus height and surface area in the duodenum and ileum, as well as a higher (P < 0.05) villus height to crypt depth ratio in the jejunum. The expression levels of jejunal CLDN1 and ZO-1 were also higher (P < 0.05) in the ACTM100 and SAL groups compared to the PC and ACTM50 groups at 24 days of age. In conclusion, while using ACTM in broiler diets at 50 % of the commercial recommended levels maintained performance and physiological responses, complete replacement with ACTM improved growth performance and intestinal health characteristics, similar to salinomycin under Eimeria challenge conditions.

Dietary Crude Protein and Lysine Levels Affect Meat Quality and Myofiber Characteristic of Slow-Growing Chicken

This study aimed to investigate the effects of dietary crude protein (CP) and lysine levels on growth performance, slaughter performance, meat quality, and myofiber characteristics of slow-growing chicken. A 3 × 3 factorial experiment was arranged, and the chickens were fed with 3 levels of dietary CP (16.0%, 17.0%, 18.0%) and 3 levels of dietary lysine (0.69%, 0.84%, 0.99%). A total of 540 8-week-old Beijing-You Chicken (BYC) female growing chickens were randomly allocated to 9 groups, 5 replicates per group, and 12 chickens per replicate. The birds were randomly allocated to one of the 9 experimental diets. Growth performance, slaughter performance, meat quality, and myofiber characteristics were determined at 16 weeks of age. The results showed that dietary CP level and the interaction of dietary CP and lysine levels affected average feed intake (AFI) (p < 0.05). The AFI in the 16.0% CP and 17.0% CP groups was higher than in the 18.0% CP group (p < 0.05). Dietary CP levels significantly affected body weight gain (BWG) (p < 0.05) at 9 to 16 weeks. The 18.0% CP group had the highest BWG (93.99 g). Dietary CP levels affected the percentage of leg muscle yield, and the percentage of leg muscle yield of the 16.0% CP group was significantly lower than that in the other two groups (p < 0.05). Dietary CP and lysine levels alone and their interactions did not affect pH24h, drip loss, and cooking loss of breast muscle (p > 0.05). The shear force of the 18.0% CP group (29.55 N) was higher than that in the other two groups (p < 0.01). Dietary CP level affected myofiber characteristic (p < 0.01), with the lowest myofiber density (846.35 p·mm-2) and the largest myofiber diameter (30.92 μm) at 18.0% CP level. Dietary lysine level affected myofiber diameter, endomysium thickness, perimysium thickness (p < 0.01), with the largest myofiber diameter (29.29 μm) obtained at 0.84% lysine level, the largest endomysium thickness (4.58 μm) at 0.69% lysine level, and the largest perimysium thickness (9.26 μm) at 0.99% lysine level. Myofiber density was negatively correlated with myofiber diameter and endomysium thickness (R = -0.883, R = -0.523, p < 0.01); perimysium thickness had a significant negative correlation with shear force (R = -0.682, p < 0.05). Therefore, reducing dietary CP level and adding appropriate lysine can reduce myofiber diameter and increase perimysium thickness, reducing shear force and improving meat tenderness. A high lysine level (0.99%) in the low-CP (16.0%) diet can improve meat tenderness by regulating the myofiber characteristic without affecting production performance.

Phase-specific outcmes of arginine or branched-chain amino acids supplementation in low crude protein diets on performance, nutrient digestibility, and expression of tissue protein synthesis and degradation in broiler chickens infected with mixed Eimeria spp

A 35-d study investigated the impact of dietary supplementation with Arginine (Arg) or branched-chain amino acids (BCAA) of broilers receiving low-protein diets whilst infected with mixed Eimeria species. All birds were given the same starter (d0-10) and finisher (d28-35) diets. The 4 grower diets used were a positive control (PC) with adequate protein (18.5%), a low protein diet (NC;16.5% CP), or the NC supplemented with Arg or BCAA. Supplemental AA was added at 50% above the recommended levels. The treatments were in a 4 × 2 factorial arrangement, with 4 diets, with or without Eimeria inoculation on d14. Birds and feed were weighed after inoculation in phases: prepatent (d14-17), acute (d18-21), recovery (d22-28), and compensatory (d29-35). Ileal digesta, jejunum, and breast tissue were collected on d21, 28, and 35. There was no diet × Eimeria inoculation on growth performance at any phase. Infected birds weighed less and consumed less feed (P < 0.05) in all phases. In the prepatent and acute phases, birds on the Arg diets had higher weight gain (P < 0.05) and lower FCR, similar to PC, when compared to NC and BCAA-fed ones. Infection reduced AA digestibility on d21 and 28 (Met and Cys). However, birds that received supplemental AA had higher digestibility (P < 0.05) of their respective supplemented AA on d 21 only. Infected birds had lower (P < 0.05) BO + AT and higher PEPT1 expression on d21. There was a diet × Eimeria interaction (P = 0.004) on gene expression at d28; 4EBP1 genes were significantly downwardly expressed (P < 0.05) in birds fed Arg diet, irrespective of infection. Infected birds exhibited an upward expression (P < 0.05) of Eef2 on d21 and d28 but experienced a downward expression on d35. Supplemental Arg and BCAA had variable effects on growth performance, apparent ileal AA digestibility, and genes of protein synthesis and degradation, but the effect of Arg on promoting weight gain, irrespective of the Eimeria challenge, was more consistent.

Effects of methionine supplementation in a reduced protein diet on growth performance, oxidative status, intestinal health, oocyst shedding, and methionine and folate metabolism in broilers under Eimeria challenge

BACKGROUND

This study investigated effects of different methionine (Met) supplementation levels in a reduced protein diet on growth performance, intestinal health, and different physiological parameters in broilers under Eimeria challenge. A total of 600 fourteen-day-old Cobb500 male broilers were challenged with E. maxima, E. tenella, and E. acervulina, and randomly allocated in a 2 × 5 factorial arrangement. Birds received normal protein diets (20% crude protein, NCP) or reduced protein diets (17% crude protein, LCP), containing 2.8, 4.4, 6.0, 7.6, and 9.2 g/kg of Met.

RESULTS

On 6 and 9 days post inoculation (DPI), increasing Met level linearly improved the growth performance (P < 0.05). Total oocyst shedding linearly increased as Met level increased (P < 0.05). Duodenal villus height (VH):crypt depth (CD) in the LCP groups were higher on 6 DPI (P < 0.01) while lower on 9 DPI (P < 0.05) compared to the NCP groups. Jejunal CD and duodenal VH:CD changed quadratically as Met level increased (P < 0.05). On 6 DPI, liver glutathione (GSH) and glutathione disulfide (GSSG) linearly increased as Met level increased (P < 0.05). On 9 DPI, GSSG quadratically increased, whereas GSH:GSSG quadratically decreased as Met levels increased (P < 0.05). The expression of amino acid transporters linearly decreased as Met level increased (P < 0.05). The expression of zonula occludens 2 and claudin-1 linearly increased on 6 DPI whereas decreased on 9 DPI as Met level increased (P < 0.05). The expressions of cytokines were lower in the LCP groups than the NCP groups (P < 0.05). Interaction effects were found for the expression of IL-10 and TNFα on 6 DPI (P < 0.05), where it only changed quadratically in the NCP group as Met level increased. The expression of Met and folate metabolism genes were lower in the LCP groups than the NCP groups on 9 DPI (P < 0.05). The expression of these genes linearly or quadratically decreased as Met level increased (P < 0.05).

CONCLUSION

These results revealed the regulatory roles of Met in different physiological parameters including oxidative status, intestinal health, and nutrient metabolism in birds fed reduced protein diet and challenged with Eimeria.

Effects of Dietary Inclusion of a Proprietary Combination of Quillaja saponaria and Yucca schidigera on Intestinal Permeability and Immune Response in Broiler Chickens during a Coccidia Challenge

This study assessed the impact of Magni-Phi Ultra (MPU) inclusion on intestinal integrity and immunity in broiler chickens challenged with coccidia during peak and recovery phases. A total of 128 male Ross 708 broiler chicks were randomly allotted to one of four treatment groups (four chicks/cage). Treatments included an uninfected control (UUC); a coccidial challenge (CC) infected control (IUC); a CC fed salinomycin at 66 ppm (SAL); and a CC fed Magni-Phi Ultra at 0.11 g/kg of diet (MPU). At 16 days post-hatch, all birds in the CC groups were orally gavaged with a 3× dose of a live coccidia vaccine. At 5 dpi, the birds fed MPU and SAL showed decreased plasma FITC-d, oocyte shedding, and lesion scores and higher BWG compared to the IUC birds (p < 0.05). Jejunum IL-17, IL-10, and IFN-ϒ mRNA expression was higher in the IUC compared to the UUC (p < 0.05) group at 5 dpi. At 12 dpi, the birds fed MPU or SAL had lower plasma FITC-d and jejunum IFN-ϒ and IL-10 mRNA expression compared to the IUC birds (p < 0.05). This study indicates that MPU supports intestinal integrity and mucosal immune responses during the peak and recovery phases of infection, which may lead to improved health and performance.

Supplementing low protein diets with methionine or threonine during mixed Eimeria challenge

We investigated the effects of supplementing low protein diets with methionine (Met) or threonine (Thr) during a mixed Eimeria (consisting of E. acervulina, E. maxima and E. tenella) challenge in broilers. All birds were fed the same starter diet (d1-9) and finisher diet (d28-35) which met Cobb 500 nutrient specifications. Birds were allocated to 1 of 4 dietary treatments from d9 to 28: a standard protein diet (19% CP); a low protein diet (16% CP); or the low protein diet supplemented with Met or Thr at 50% above recommendations. On d14, half of the birds were challenged, and half of the birds were unchallenged. From d14 to 28, feed intake was recorded daily and BW every 3 or 4 d. Oocyst excretion was measured daily from d18 to 27. On d21 and 28, 3 birds per pen were euthanized to assess nutrient digestibility, cytokine expression and intestinal histology. During the acute stage of the challenge, challenged birds reduced ADFI and ADG (P < 0.05). In the pre-patent and recovery stages, birds given the 16% CP diets increased ADFI (P < 0.05), meanwhile there were no differences in ADG in these stages (P > 0.05). Nutrient digestibility was reduced in challenged birds in the acute stage (P < 0.05) but tended to be greater than in unchallenged birds during the recovery stage. There was no significant effect of diet on oocyst excretion or intestinal histology (P > 0.05). Interactions were observed between diet and challenge on IL-10 and IL-21 expression in the cecal tonsils during the acute stage of the challenge (P < 0.05), due to reduced IL-10 expression in challenged Thr birds and greater IL-21 expression in challenged Met birds. Supplementation with Thr or Met had limited effects on the outcomes of a mixed Eimeria challenge but provides benefits to the host by enhancing their immune response.

Effect of dietary treatments on performance, oocysts shedding and lesion scores in broiler chickens experimentally challenged with Eimeria infection

Although anticoccidials effectively control coccidiosis, a needed reduction in the reliance on antimicrobials in animal production leads to the exploration of alternative compounds. The present study aimed to test five different dietary treatments to counteract the negative impact of coccidiosis on broiler chickens' health and performance. 1-day-old male Ross 308 broilers (n = 960) were randomly assigned to one of eight treatments, with six cages per treatment (20 birds/cage). To the diet of the broiler chickens of treatments (Trt) 1-5, a synbiotic was added from d0-10. From d10-28, birds of Trt1 and Trt2 were fed synbiotics, whereas birds of Trt3 were fed diets with glutamine, and birds of Trt4 and Trt5 were fed diets with a combination of β-glucans and betaine. From d28-35 onwards, birds of Trt1 were fed a diet with a synbiotic, whereas birds of Trt2-4 received diets with glutamine, and birds of Trt5 were fed a non-supplemented diet. Birds of the positive control group (PC; Trt6) were fed a standard diet supplemented with an anticoccidial (Decoquinate). The challenged negative control (NCchall; Trt7) and non-challenged negative control (NC) Trt8 were fed a standard diet without anticoccidial or other dietary treatment. At 7 days (d) of age, all birds were inoculated with 1 023, 115, and 512 sporulated oocysts of E. acervulina, E. maxima, and E. tenella, respectively, except for Trt8. Body weight gain (BWG), feed intake, and feed conversion ratio were assessed for each feeding phase (d0-10, d10-28 and d28-35) and overall experimental period (d0-35). Oocyst shedding, Eimeria lesion scores, cecal length, and relative weight were assessed at d13, d22, d28 and d35. Additionally, oocyst shedding was determined at d9 and d17. Litter quality was evaluated at d27 and d34, and footpad lesions at d34. During the starter (d0-10) and finisher (d28-35) periods, performance did not differ between the treatments. During the grower period (d10-28), Trt6 (PC) and Trt8 (NC) chickens had the highest BWG of all treatments (P < 0.001). Dietary treatment had no effect on litter quality and severity of footpad lesions. In the PC group (Trt6), low oocyst excretion and lesion scores were found. When comparing Trt1-5 with NCchall (Trt7), none of the treatments significantly reduced oocyst output or lesion scores. In conclusion, in this experiment, none of the dietary treatments performed similar or better compared to the PC group (Trt6) regarding performance or reducing Eimeria oocyst shedding or lesion scores.

Effects of L-Leu-L-Leu peptide on growth, proliferation, and apoptosis in broiler intestinal epithelial cells

Small peptides are nutrients and bioactive molecules that have dual regulatory effects on nutrition and physiology. They are of great significance for maintaining the intestinal health and production performance of broilers. We here cultured the primary small intestinal epithelial cells (IEC) of chicken in a medium containing L-Leu (Leu) and L-Leu-L-Leu (Leu-Leu) for 24 h. The untreated cells were considered as the control group. The growth, proliferation, and apoptosis of IEC were examined. By combining RNA-seq and label-free sequencing technology, candidate genes, proteins, and pathways related to the growth, proliferation, and apoptosis of IEC were screened. Immunofluorescence detection revealed that the purity of the isolated primary IEC was >90%. The Leu-Leu group significantly promoted IEC growth and proliferation and significantly inhibited IEC apoptosis, and the effect was better than those of the Leu and control groups. Using transcriptome sequencing, four candidate genes, CCL20, IL8L1, IL8, and IL6, were screened in the Leu group, and one candidate gene, IL8, was screened in the Leu-Leu group. Two candidate genes, IL6 and RGN, were screened in the Leu-Leu group compared with the Leu group. Nonquantitative proteomic marker sequencing results revealed that through the screening of candidate proteins and pathways, found one growth-related candidate protein PGM3 and three proliferation-related candidate proteins RPS17, RPS11, and RPL23, and two apoptosis-related candidate proteins GPX4 and PDPK1 were found in the Leu-Leu group compared with Leu group. In short, Leu-Leu could promote IEC growth and proliferation and inhibit IEC apoptosis. On combining transcriptome and proteome sequencing technologies, multiple immune- and energy-related regulatory signal pathways were found to be related to IEC growth, proliferation, and apoptosis. Three candidate genes of IL8, IL6, and RGN were identified, and six candidate proteins of PGM3, RPS17, RPS11, RPL23, GPX4, and PDPK1 were involved in IEC growth, proliferation, and apoptosis. The results provide valuable data for preliminarily elucidating small peptide-mediated IEC regulation pathways, improving the small peptide nutrition theoretical system, and establishing small peptide nutrition regulation technology.

Effects of phytase supplementation on broilers fed with calcium and phosphorus-reduced diets, challenged with Eimeria maxima and Eimeria acervulina: influence on growth performance, body composition, bone health, and intestinal integrity

An experiment was conducted to evaluate the effects of phytase in calcium (Ca) and available phosphorous (avP)-reduced diet on growth performance, body composition, bone health, and intestinal integrity of broilers challenged with Eimeria maxima and Eimeria acervulina. A total of 672 14-day-old male broilers were allocated to a 2 × 4 factorial arrangement with 6 replicates per treatment and 14 birds per replicate. Two factors were Eimeria challenge and 4 dietary treatments: 1) a positive control (PC; 0.84% Ca and 0.42% avP); 2) a negative control (NC; 0.74% Ca and 0.27% avP); 3) NC + 500 FTU/Kg of phytase (NC + 500PHY); and 4) NC + 1,500 FTU/Kg of phytase (NC + 1500PHY). On d 14, birds in the Eimeria-challenged groups received a solution containing 15,000 sporulated oocysts of E. maxima and 75,000 sporulated oocysts of E. acervulina via oral gavage. At 5 d postinoculation (DPI), the challenged birds showed a higher (P < 0.01) FITC-d level than the unchallenged birds. While the permeability of the NC group did not differ from the PC group, the phytase supplementation groups (NC + 500PHY and NC + 1500PHY) showed lower (P < 0.05) serum FITC-d levels compared to the NC group. Interaction effects (P < 0.05) of Eimeria challenge and dietary treatments on feed intake (FI), mucin-2 (MUC2) gene expression, bone ash concentration, and mineral apposition rate (MAR) were observed. On 0 to 6 and 0 to 9 DPI, Eimeria challenge decreased (P < 0.01) body weight (BW), body weight gain (BWG), FI, bone mineral density (BMD), bone mineral content (BMC), bone area, fat free bone weight (FFBW), bone ash weight, bone ash percentage and bone ash concentration; and it showed a higher FCR (P < 0.01) compared to the unchallenged group. The reduction Ca and avP in the diet (NC) did not exert adverse effects on all parameters in birds, and supplementing phytase at levels of 500 or 1,500 FTU/Kg improved body composition, bone mineralization, and intestinal permeability, with the higher dose of 1,500 FTU/Kg showing more pronounced enhancements. There was an observed increase in FI (P < 0.01) when phytase was supplemented at 1,500 FTU/Kg during 0 to 6 DPI. In conclusion, results from the current study suggest that dietary nutrients, such as Ca and avP, can be moderately reduced with the supplementation of phytase, particularly in birds infected with Eimeria spp., which has the potential to save feed cost without compromising growth performance, bone health, and intestinal integrity of broilers.

Coccidiosis in Egg-Laying Hens and Potential Nutritional Strategies to Modulate Performance, Gut Health, and Immune Response

Avian coccidiosis, despite advancements in management, nutrition, genetics, and immunology, still remains the most impactful disease, imposing substantial economic losses to the poultry industry. Coccidiosis may strike any avian species, and it may be mild to severe, depending on the pathogenicity of Eimeria spp. and the number of oocysts ingested by the bird. Unlike broilers, low emphasis has been given to laying hens. Coccidiosis in laying hens damages the gastrointestinal tract and causes physiological changes, including oxidative stress, immunosuppression, and inflammatory changes, leading to reduced feed intake and a drastic drop in egg production. Several countries around the world have large numbers of hens raised in cage-free/free-range facilities, and coccidiosis has already become one of the many problems that producers have to face in the future. However, limited research has been conducted on egg-laying hens, and our understanding of the physiological changes following coccidiosis in hens relies heavily on studies conducted on broilers. The aim of this review is to summarize the effect of coccidiosis in laying hens to an extent and correlate it with the physiological changes that occur in broilers following coccidiosis. Additionally, this review tries to explore the nutritional strategies successfully used in broilers to mitigate the negative effects of coccidiosis in improving the gut health and performance of broilers and if they can be used in laying hens.

Impacts of varying methionine to cysteine supplementation ratios on growth performance, oxidative status, intestinal health, and gene expression of immune response and methionine metabolism in broilers under Eimeria spp. challenge

A study was conducted to investigate effects of different methionine (Met) to cysteine (Cys) supplementation ratios (MCR) on growth performance, oxidative status, intestinal health, immune responses, and methionine metabolism in broilers under Eimeria challenge. A total of 720 male Cobb500 broilers (14-day-old) were allocated in a 2 × 5 factorial arrangement (5 diets, with or without challenge) with 6 replicates per treatment. The total sulfur amino acid concentrations were consistent across treatments meeting the breeder's recommendation, only MCR varied. The diets were labeled as MET100; MET75; MET50; MET25; and MET0, representing MCR of 100:0; 75:25; 50:50; 25:75; and 0:100, respectively. Data were analyzed by 2-way ANOVA and orthogonal polynomial contrast. Growth performance declined linearly or quadratically as MCR decreased (P < 0.01). On 6-day postinoculation (DPI), interaction effects (P < 0.01) were found; BW and body weight gain were lower in MET0 compared to the other treatments in the nonchallenged groups, whereas not in the challenged groups. On 6 and 9 DPI, serum total antioxidant capacity linearly decreased as MCR decreased (P < 0.05). Hepatic activities of glutathione peroxidase on 6 DPI and superoxide dismutase on 9 DPI changed quadratically as MCR decreased (P < 0.05). The digestibility of Met linearly decreased whereas the digestibility of Cys linearly increased as MCR decreased. The ileal crypt depth linearly decreased as MCR decreased (P < 0.01) on 6 DPI. The expression of transforming growth factor beta on 6 and 9 DPI, tumor necrotic factor alpha and interleukin 10 on 9 DPI changed quadratically as MCR decreased (P < 0.05). Eimeria challenge increased expression of Met adenosyltransferase and cystathionine gamma-lyase, whereas decreasing the expression of other Met metabolism genes (P < 0.01) on 6 DPI. Expression of Met metabolism genes linearly increased as MCR decreased (P < 0.05). In conclusion, different Met to Cys supplementation ratios exerted linearly or quadratically effects on the growth performance, oxidative status, intestinal health, and metabolism of Met in broiler chickens under Eimeria infection.

Graded levels of Eimeria infection linearly reduced the growth performance, altered the intestinal health, and delayed the onset of egg production of Hy-Line W-36 laying hens when infected at the prelay stage

The aim of this experiment was to investigate how different levels of Eimeria infection affect the performance, intestinal health, oxidative status, and egg production of Hy-Line W-36 pullets and laying hens. Three hundred and sixty Hy-Line W-36 pullets, aged 15 wk, were randomly distributed into 5 treatment groups, each comprising 6 replicates and a nonchallenged control. At 15 wk, pullets were inoculated with different levels of mixed Eimeria species as high-dose, medium-high, medium-low, and low-dose treatments. The growth performance and average daily feed intake (ADFI) were measured from 0- to 18-days postinoculation (DPI), whereas hen day egg production (HDEP) was recorded from wk 19. The markers of gastrointestinal health and oxidative status were measured at 6 DPI, 14 DPI, and 23 wk of age. The findings revealed a significant linear reduction in growth performance in response to increased Eimeria challenge dosage on 6 and 14 DPI (P < 0.0001, P-L < 0.0001). An interaction between the graded level of Eimeria infection and DPI was observed for ADFI. The challenged pullets showed a reduction in ADFI starting at 4 DPI, which persisted until 14 DPI, when ADFI recovered back to normal. The most significant drop in feed intake was observed in 6 DPI in all the Eimeria-infected groups. The markers of gastrointestinal health (gastrointestinal permeability and tight junction proteins) were upregulated in challenged pullets because of infection, whereas the relative mRNA expression of key nutrient transporters was downregulated following infection on 6 and 14 DPI (P < 0.05). As a result of an infection on 6 DPI, the oxidative equilibrium was shifted toward the oxidative stress, and at the same time, upregulation of proinflammatory and inflammatory cytokines was observed (P < 0.05). An interaction between the Eimeria challenge dosage and bird age was observed for HDEP (P = 0.0427). The pullets infected with Eimeria started to lay eggs later than the Control birds. However, the HDEP of the challenged groups became similar to Control only at wk 22, 3 wk after laying eggs. In conclusion, coccidiosis reduced growth performance, altered gastrointestinal health, induced oxidative stress, and delayed egg production when infected at the prelay stage of pullets and negatively impacted the laying hens' overall performance.

Impacts of phytase and coccidial vaccine on growth performance, nutrient digestibility, bone development, and intestinal gene expression of broilers fed a nutrient reduced diet

An experiment was conducted to evaluate effects of phytase and coccidial vaccine on growth performance, bone ash, bone 3-D microstructure, nutrient digestibility, and gene expression of intestinal biomarkers in broilers fed a regular or nutrient-reduced diet. The experiment was conducted in a 2 × 4 factorial arrangement with 6 replicates per treatment and 10 birds per replicate. Two main factors were coccidial vaccine and dietary treatments. The dietary treatments included: 1) a positive control (PC; normal nutrient levels); 2) a negative control (NC; with a reduction of 0.15% of Ca and avP and 5% of essential amino acid (EAA) and crude protein relative to PC); 3) NC + 500 FTU/kg of phytase; and 4) NC + 1,500 FTU/kg of phytase. No interaction effect of phytase and coccidial vaccine on growth performance, bone ash, and apparent ileal digestibility (AID) was observed. For the main effect, birds fed the NC diet showed lower (P = 0.007) BWG during d 0 to 21 compared to PC birds, whereas supplementing 500 or 1,500 FTU/kg phytase increased BWG to the similar level to the PC. During d 0 to 21, vaccinated birds had a lower (P < 0.001) FI and better (P = 0.045) FCR compared to unvaccinated birds. Birds fed the NC diet resulted a decrease in tibia fat-free dry bone weight (P = 0.012), ash weight (P = 0.005), ash percentage (P < 0.001), and ash concentration (P = 0.019) compared to the PC group at d 21, whereas supplementing phytase at 500 or 1,500 FTU/kg in NC diet was able to improve these bone parameters to the similar level to the PC; however, vaccination did not have any effect on bone ash. Similarly, birds fed with the NC diet showed had significant lower bone microstructure levels including bone volume, bone mineral density, and bone mineral content (P < 0.001), and supplementing phytase at 1,500 FTU/kg improved these parameters. Vaccination improved AID of nitrogen (P < 0.001). Birds from the NC and both phytase supplementation groups had a higher (P = 0.001) AID of Ca compared to the PC. Supplementing phytase at 500 FTU/kg or 1,500 FTU/kg improved (P < 0.001) AID of P compared to the NC. Additionally, the NC had a lower AID of DM than the PC, whereas supplementing phytase at 500 FTU/kg or 1,500 FTU/kg improved DM digestibility (P = 0.0299). In conclusion, supplementation of phytase at 500 or 1,500 FTU/kg improved growth performance, bone mineralization, and nutrient digestibility regardless of vaccination, with a more pronounced effect when supplementing phytase at 1,500 FTU/kg.

The Functional Roles of Methionine and Arginine in Intestinal and Bone Health of Poultry: Review

This review explores the roles of methionine and arginine in promoting the well-being of poultry, with a specific focus on their impacts on intestinal and bone health. The metabolic pathways of methionine and arginine are elucidated, highlighting their distinct routes within the avian system. Beyond their fundamental importance in protein synthesis, methionine and arginine also exert their functional roles through their antioxidant capacities, immunomodulating effects, and involvement in the synthesis of metabolically important molecules such as S-adenosylmethionine, nitric oxide, and polyamines. These multifaceted actions enable methionine and arginine to influence various aspects of intestinal health such as maintaining the integrity of the intestinal barrier, regulating immune responses, and even influencing the composition of the gut microbiota. Additionally, they could play a pivotal role in promoting bone development and regulating bone remodeling, ultimately fostering optimal bone health. In conclusion, this review provides a comprehensive understanding of the potential roles of methionine and arginine in intestinal and bone health in poultry, thereby contributing to advancing the nutrition, overall health, and productivity of poultry in a sustainable manner.

Effects of Different Eimeria Inoculation Doses on Growth Performance, Daily Feed Intake, Gut Health, Gut Microbiota, Foot Pad Dermatitis, and Eimeria Gene Expression in Broilers Raised in Floor Pens for 35 Days

The study was conducted to investigate the effects of different Eimeria inoculation doses on the growth performance, gut ecosystem, and body composition of broilers in floor pens for 35 days. A total of 750 15-day-old broilers were allocated to five experimental groups with six replicate pens. The five experimental groups included unchallenged control (CON); Eimeria dose 1 (ED1): E. acervulina: 31,250/E. maxima: 6250/E. tenella: 6250; Eimeria dose 2 (ED2): E. acervulina: 62,500/E. maxima: 12,500/E. tenella: 12,500; Eimeria dose 3 (ED3): E. acervulina: 125,000/E. maxima: 25,000/E. tenella: 25,000; and Eimeria dose 4 (ED4): E. acervulina: 250,000/E. maxima: 50,000/E. tenella: 50,000. On D 21, BW were linearly reduced by increased Eimeria inoculation doses (p < 0.01). On D 35, the Eimeria challenge groups had significantly lower BW compared to the CON group. Increased Eimeria inoculation doses linearly decreased crude fat (CF) (p < 0.01) on D 21. Increased Eimeria inoculation doses tended to increase the relative abundance of the phylum Proteobacteria (p = 0.098) on D 21. On D 35, lean:fat was linearly reduced by increased Eimeria inoculation doses (p < 0.05). Eimeria infection negatively influenced growth performance and gut health in broilers in the acute phase, and the negative effects were prolonged to D 35 in floor pen conditions.

The effects of arginine and branched-chain amino acid supplementation to reduced-protein diet on intestinal health, cecal short-chain fatty acid profiles, and immune response in broiler chickens challenged with Eimeria spp

We investigated the effects of supplementing arginine (Arg) and branched-chain amino acids (BCAA) in broilers fed reduced-protein diets and challenged with Eimeria spp. All birds were fed the same starter diet meeting Cobb 500 nutrient specifications from d 1 to 9. Four grower diets: positive control (PC) with 20.0% crude protein (CP); reduced-protein negative control (NC) with 17.5% CP; or NC supplemented with Arg or BCAA at 50% above recommendations (ARG or BCAA) were fed to the birds from d 9 to 28. Birds were allocated in a 2 × 4 factorial arrangement (4 diets, each with or without challenge), with 8 replicates per treatment. On d 14, the challenge groups were orally gavaged with mixed Eimeria spp. Intestinal permeability was higher (P < 0.05) in NC than PC, whereas the permeability of ARG and BCAA groups did not differ significantly from PC. On d 28, a significant interaction (P < 0.01) was observed in CD8⁺: CD4⁺ ratios in cecal tonsils (CT), Eimeria challenge increased the ratios in all groups except for the ARG group. On d 21, a significant interaction was found for CD4⁺CD25⁺ percentages in CT (P < 0.01) that Eimeria challenge increased the percentages only in PC and NC groups. On d 21 and 28, significant interactions (P < 0.01) were found for macrophage nitric oxide (NO) production. In nonchallenged birds, NO was higher in the ARG group than other groups, but in challenged birds, NO was higher in both ARG and BCAA groups. On d 21, a significant interaction was found for bile anticoccidial IgA concentrations (P < 0.05) that Eimeria challenge increased IgA only in NC and ARG groups. The results suggest that a reduced-protein diet exacerbates the impact of the Eimeria challenge on intestinal integrity, but this could be mitigated by Arg and BCAA supplementations. Arginine and BCAA supplementations in reduced-protein diets could be beneficial for broilers against Eimeria infection by enhancing the immune responses. The beneficial effects of Arg supplementation tended to be more pronounced compared to BCAA supplementation.

Nutritional Strategies to Improve Meat Quality and Composition in the Challenging Conditions of Broiler Production: A Review

Poultry meat is becoming one of the most important animal protein sources for human beings in terms of health benefits, cost, and production efficiency. Effective genetic selection and nutritional programs have dramatically increased meat yield and broiler production efficiency. However, modern practices in broiler production result in unfavorable meat quality and body composition due to a diverse range of challenging conditions, including bacterial and parasitic infection, heat stress, and the consumption of mycotoxin and oxidized oils. Numerous studies have demonstrated that appropriate nutritional interventions have improved the meat quality and body composition of broiler chickens. Modulating nutritional composition [e.g., energy and crude protein (CP) levels] and amino acids (AA) levels has altered the meat quality and body composition of broiler chickens. The supplementation of bioactive compounds, such as vitamins, probiotics, prebiotics, exogenous enzymes, plant polyphenol compounds, and organic acids, has improved meat quality and changed the body composition of broiler chickens.

Effects of dietary sulfur amino acid levels on growth performance and intestinal immunity in broilers vaccinated and subsequently infected with coccidiosis

Coccidia vaccination is a common practice in the poultry industry. However, research is lacking regarding the optimal nutritional support for coccidia vaccinated broilers. In this study, broilers were vaccinated with coccidia oocyst at hatch and were fed with a common starter diet from 1 to 10 d. On d 11, the broilers were randomly assigned to groups in a 4 × 2 factorial arrangement. Briefly, the broilers were fed one of four diets containing 0.6, 0.8, 0.9, and 1.0% of standardized ileal digestible methionine plus cysteine (SID M+C), respectively, from 11 to 21 d. On d 14, the broilers from each diet group were orally gavaged with either PBS (Mock challenge) or Eimeria oocysts. Compared to PBS-gavaged broilers and regardless of dietary SID M+C levels, the Eimeria-gavaged broilers had 1) decreased gain-to-feed ratio (15-21 d, P = 0.002; 11-21 d, P = 0.011); 2) increased fecal oocysts (P < 0.001); 3) increased plasma anti-Eimeria IgY (P = 0.033); and 4) increased intestinal luminal interleukin-10 (IL-10; duodenum, P = 0.039; jejunum, P = 0.018) and gamma interferon (IFN-γ; duodenum, P < 0.001; jejunum, P = 0.017). Regardless of Eimeria gavage, broilers fed 0.6% SID M+C had decreased (P<0.001) body weight gain (15-21 and 11-21 d) and gain-to-feed ratio (11-14, 15-21, and 11-21 d) when compared to those fed ≥ 0.8% SID M+C. Eimeria challenge increased (P < 0.001) duodenum lesions when the broilers were fed with 0.6, 0.8, and 1.0% SID M+C, and increased (P = 0.014) mid-intestine lesions when the broilers were fed with 0.6 and 1.0% SID M+C. An interaction between the two experimental factors was detected on plasma anti-Eimeria IgY titers (P = 0.022), as coccidiosis challenge increased plasma anti-Eimeria IgY titers only when the broilers were fed with 0.9% SID M+C. In summary, the dietary SID M+C requirement for grower (11-21 d) broilers vaccinated with coccidiosis was ranged from 0.8 to 1.0% for optimal growth performance and intestinal immunity, regardless of coccidiosis challenge.

Different amino acid supplementation patterns in low-protein diets on growth performance and nitrogen metabolism of goslings from 1 to 28 days of age

The investigation aimed to explore the suitable amino acid (AA) supplementation pattern for goslings under low-protein diets. A total of 364 1-day-old male goslings were randomly divided into 4 experimental groups, with 7 pens containing 13 goslings each. The 4 groups were control (CP, 18.55%), LPM (CP, 15.55% + major AA), LPA (CP, 15.55% + all AA), and LPR (CP, 15.55% + AA content reduced proportionally to the control's CP). The corn-soybean meal diets are formulated according to the ideal AA model of goose and its nutritional requirements. The results indicated that the ADG and BW were the lowest, and the F: G was the highest in LPR (P < 0.05); the other three groups were not significantly different (P > 0.05). The ADFI and mortality were not different among all the groups (P > 0.05). Among the AA content in serum and breast muscle, lysine in serum significantly decreased compared with the control (P < 0.05). The UREA content was approximately 2-fold higher in the LPR group than in the LPM and LPA groups (P < 0.05). No difference in IgA, IgG, IgM, and IgE levels was observed among the groups (P > 0.05). The nitrogen excretion was decreased in LPM and LPA compared to the control and LPR (P < 0.05). Nitrogen deposition did not differ among groups (P > 0.05). Nitrogen utilization was highest in the LPA and LPM groups, followed by the control group and LPR (P < 0.05). In conclusion, the patterns of supplementation of major AA and all AA in low-protein diets (CP, 15.55%) had no adverse effect on the growth performance compared with the control (CP, 18.55%) of the goslings. Besides, the two patterns could decrease nitrogen excretion and increase nitrogen utilization. Furthermore, from the perspective of dietary cost and environmental protection, the pattern of supplementing major AA in a corn-soybean meal low-protein diet is suggested.

Effects of arginine replacement with L-citrulline on the arginine/nitric oxide metabolism in chickens: An animal model without urea cycle

BACKGROUND

This study examined the efficacy of L-citrulline supplementation on the arginine/nitric oxide metabolism, and intestinal functions of broilers during arginine deficiency. A total of 288 day-old Arbor Acre broilers were randomly assigned to either an arginine deficient basal diet (NC diet), NC diet + 0.50% L-arginine (PC diet), or NC diet + 0.50% L-citrulline (NCL diet). Production performance was recorded, and at 21 days old, chickens were euthanized for tissue collection.

RESULTS

The dietary treatments did not affect the growth performance of broilers (P > 0.05), although NC diet increased the plasma alanine aminotransferase, urate, and several amino acids, except arginine (P < 0.05). In contrast, NCL diet elevated the arginine and ornithine concentration higher than NC diet, and it increased the plasma citrulline greater than the PC diet (P < 0.05). The nitric oxide concentration in the kidney and liver tissues, along with the plasma and liver eNOS activities were promoted by NCL diet higher than PC diet (P < 0.05). In the liver, the activities of arginase 1, ASS, and ASL, as well as, the gene expression of iNOS and OTC were induced by PC diet greater than NC diet (P < 0.05). In the kidney, the arginase 1, ASS and ASL enzymes were also increased by PC diet significantly higher than the NC and NCL diets. Comparatively, the kidney had higher abundance of nNOS, ASS, ARG2, and OTC genes than the liver tissue (P < 0.05). In addition, NCL diet upregulated (P < 0.05) the mRNA expression of intestinal nutrient transporters (EAAT3 and PEPT1), tight junction proteins (Claudin 1 and Occludin), and intestinal mucosal defense (MUC2 and pIgR). The intestinal morphology revealed that both PC and NCL diets improved (P < 0.05) the ileal VH/CD ratio and the jejunal VH and VH/CD ratio compared to the NC fed broilers.

CONCLUSION

This study revealed that NCL diet supported arginine metabolism, nitric oxide synthesis, and promoted the intestinal function of broilers. Thus, L-citrulline may serve as a partial arginine replacement in broiler's diet without detrimental impacts on the performance, arginine metabolism and gut health of chickens.

Effects of tannic acid supplementation on growth performance, gut health, and meat production and quality of broiler chickens raised in floor pens for 42 days

A study was conducted to investigate the effects of tannic acid (TA) supplementation on growth performance, gut health, antioxidant capacity, gut microbiota, and meat yield and quality in broilers raised for 42 days. A total of 700 one-day-old male broiler chickens (Cobb500) were allocated into 5 treatments with 7 replicates of 20 birds per pen. There were five treatments: 1) tannic acid 0 (TA0: basal diet without TA); 2) tannic acid 0.25 (TA0.25: basal diet+0.25 g/kg TA); 3) tannic acid 0.5 (TA0.5: basal diet+0.5 g/kg TA); 4) tannic acid 1 (TA1: basal diet+1 g/kg TA); and 5) tannic acid 2 (TA2: basal diet+2 g/kg TA). The dietary phases included starter (D 0 to 18; crumble feed), grower (D 18 to 28; pellet feed), and finisher (D 28 to 42; pellet feed). On D 18, the supplementation of TA linearly reduced body weight (BW) and average daily feed intake (ADFI) (p < 0.05), and on D 28, the supplementation of TA linearly reduced BW, average daily gain (ADG), and feed conversion ratio (FCR) (p < 0.05). Relative mRNA expression of genes related to mucin production (MUC2), tight junction proteins (CLDN2 and JAM2), and nutrient transporters (B0AT1 and SGLT1) was linearly increased by the supplementation of TA (p < 0.05). The supplementation of TA tended to linearly increase the relative abundance of the family Enterobacteriaceae (p = 0.08) and quadratically increased the relative abundance of the families Lachnospiraceae and Ruminococcaceae in the cecal microbial communities (p < 0.05). On D 36, the ratio of the phyla Firmicutes and Bacteroidetes was quadratically reduced by the supplementation of TA (p < 0.05). On D 42, bone mineral density and the lean to fat ratio were linearly decreased by the supplementation of TA (p < 0.05). On D 43, total chilled carcass weight was linearly reduced (p < 0.05), and proportion of leg weight was increased by supplementation of TA (p < 0.05). The supplementation of TA linearly reduced pH of the breast meat (p < 0.05) and linearly increased redness (a*) (p < 0.05). Although the supplementation of TA positively influenced gut health and gut microbiota in the starter/grower phases, it negatively affected overall growth performance, bone health, and meat production in broilers on D 42.

Effect of methionine and trace minerals (zinc, copper and manganese) supplementation on growth performance of broilers subjected to Eimeria challenge

Coccidiosis is a major intestinal challenge that causes economic loss to the broiler industry. Two battery cage studies were conducted to evaluate the effect of trace minerals, source and dose of methionine on growth performance and gut health of broilers subjected to Eimeria challenge. Experiment #1 consisted of 9 treatments of 2 × 2 × 2 factorial design + 1 arrangement with main factors of methionine (Met) sources (DL-Met vs. 2-hydroxy-4-(methylthio)-butanoic acid (HMTBa)), total sulfur amino acid (TSAA) levels (high vs. low; ±5% of recommended level), and sources of trace minerals (TM) Zn:Cu:Mn in the form Inorganic trace minerals (ITM) in sulfates (80:20:100ppm) vs. mineral methionine hydroxy-analogue bis-chelate (MMHAC, 40:10:50ppm), each with 8 pens of 10 birds. Experiment #2 consisted of 2 treatments--ITM [ZnSO4:tribasic copper chloride (TBCC):MnSO4 110:125:120ppm] and MMHAC (Zn:Cu:Mn, 40:30:40ppm), each with 36 pens of 10 birds. All birds except for treatment 9 in experiment #1 were orally gavaged with 1x, 4x and 16x recommended dose of coccidiosis vaccine on d0, d7 and d14, respectively. Data were subjected to one-way and/or three-way ANOVA, and means were separated by Fisher's protected LSD test with significance at p ≤ 0.05. In experiment #1, factorial analysis revealed the main effects of TSAA level and TM, but not Met source. High TSAA level improved body weight and cumulative feed intake at 14, 20, and 27d. MMHAC improved body weight at 14, and 27d; feed intake at 14, 20, and 27d; and cumulative FCR at 27d vs. sulfates. One-way ANOVA analysis showed that birds fed MMHAC and high levels of TSAA regardless of Met source had similar body weight as unchallenged birds on d27. In experiment #2, MMHAC improved body weight and cumulative FCR, and reduced jejunal IL-17A gene expression on d28. In summary, in broilers subjected to Eimeria challenge, supplementation of the reduced levels of bis-chelated trace minerals MMHAC improved growth performance compared to high levels of ITM (sulfates or TBCC), which might partially result from better immune response, high levels of TSAA improved growth performance, Met source had no effect. Supplementation of both bis-chelated trace minerals MMHAC and high levels of TSAA could overcome the growth performance challenge issue due to coccidiosis.

The effects of xylo-oligosaccharides on regulating growth performance, nutrient utilization, gene expression of tight junctions, nutrient transporters, and cecal short chain fatty acids profile in Eimeria-challenged broiler chickens

A 21-d experiment was conducted to investigate the effects of xylo-oligosaccharides (XOS) on growth performance, nutrient utilization, gene expression of tight junctions, nutrient transporters, and cecal short chain fatty acids (SCFA) profile of broiler chickens challenged with mixed Eimeria spp. Two hundred fifty-two zero-day-old chicks were allocated to 6 treatments in a 3 × 2 factorial arrangement (corn-soybean meal diets supplemented with 0, 0.5, or 1.0 g/kg XOS; with or without Eimeria challenge). Challenged groups were inoculated with a solution containing E. maxima, E. acervulina, and E. tenella oocysts on d 15. During the infection period (d 15 to d 21), there was a significant (P < 0.05) Eimeria × XOS interaction for weight gain (WG). XOS significantly (P < 0.05) increased WG in the unchallenged birds but not in the challenged treatments. There was no significant Eimeria × XOS interaction for N and minerals utilization responses. XOS supplementation at 0.5 g/kg tended to alleviate Eimeria-induced depression in apparent ileal digestibility of DM (P = 0.052). Challenged birds had lower (P < 0.01) AME, AMEn, and total retention of N, Ca, and P. Eimeria upregulated (P < 0.01) gene expression of tight junction proteins claudin-1, junctional adhesion molecule-2, and glucose transporter GLUT1; but downregulated (P < 0.01) the peptide transporter PepT1, amino acid transporters rBAT, CAT2, y+LAT2, and zinc transporter ZnT1. XOS alleviated (P < 0.05) Eimeria-induced claudin-1 upregulation. Eimeria decreased (P < 0.05) cecal saccharolytic SCFA acetate, butyrate, and total SCFA, but increased (P < 0.05) branched chain fatty acids isobutyrate and isovalerate. The supplementation of XOS tended to decrease the concentration of isobutyrate (P = 0.08) and isovalerate (P = 0.062). In conclusion, 0.5 g/kg XOS supplementation alleviated depression in growth performance and nutrient utilization from the Eimeria challenge. In addition, supplemental XOS reversed the gene expression changes of claudin-1, also showed the potentials of alleviating the negative cecal fermentation pattern induced by Eimeria infection.

Effects of phytase and coccidial vaccine on growth performance, nutrient digestibility, bone mineralization, and intestinal gene expression of broilers

A study was conducted to evaluate effects of phytase and coccidial vaccine on growth performance, bone mineralization, nutrient digestibility, and intestinal gene expression of broiler chickens. The experiment was conducted in a 2 × 4 completely randomized factorial arrangement with 6 replicates per treatment and 10 birds each. Applications of coccidiosis vaccine and different dietary treatments were the 2 main factors in the current study. The dietary treatments included 1) a positive control (PC; 0.90% Ca and 0.45% available P: avP); 2) a negative control (NC; 0.75% Ca and 0.30% AvP); 3) NC + 500 FTU/kg of phytase (NC + 500PHY); and 4) NC + 1500 FTU/kg of phytase (NC + 1500PHY). Data were analyzed using SAS by 2-way ANOVA via GLM procedure. The statistical significance was set at P ≤ 0.05, and means were further separated using Tukey's Test. The results indicated that vaccination had no effect on growth performance except for feed intake from 0 to 14 d but negatively (P < 0.05) regulated bone ash and Ca digestibility. Birds fed with the Ca and P-reduced diet (NC) showed a lower BWG and bone ash compared to birds fed with the normal diet (PC), but supplementing phytase mitigated the negative effects on those birds. Broilers fed the NC diet had higher (P < 0.05) total Ca and P digestibility, and phytate degradation; supplementing phytase further increased P digestibility and phytate degradation of the broilers. A significant interaction (P < 0.05) between phytase and vaccination was observed, suggesting the vaccinated birds fed the PC diet and the unvaccinated birds fed the NC + 1500PHY increased calcium-sensing receptor gene expression compared with the unvaccinated birds fed the PC diet. In conclusion, in spite of coccidiosis vaccine, supplementing phytase at 1,500 FTU/kg alleviated the negative effects on growth performance, bone mineralization, and apparent ileal digestibility of P and phytate.

Effects of Tannic Acid Supplementation on Growth Performance, Oocyst Shedding, and Gut Health of in Broilers Infected with Eimeria Maxima

The purpose of this study was to evaluate effects of tannic acid (TA) on growth performance, fecal moisture content, oocyst shedding, gut permeability, lesion score, intestinal morphology, apparent ileal digestibility, and the antioxidant and immune system of broilers infected with Eimeria maxima. A total of 420 one-day-old broilers were distributed to five treatments with seven replicates of 12 birds. The five treatments were the (1) sham-challenged control (SCC; birds fed a control diet and administrated with PBS); (2) challenged control (CC; birds fed a control diet and inoculated with E. maxima); (3) tannic acid 0.5 (TA0.5; CC + 500 mg/kg TA); (4) tannic acid 2.75 (TA2.75; CC + 2750 mg/kg TA); and (5) tannic acid 5 (TA5; CC + 5000 mg/kg TA). The TA2.75 group had significantly lower gut permeability compared to the CC group at 5 days post-infection (dpi). Supplementation of TA linearly reduced oocyst shedding of E. maxima at 7 to 9 dpi (p < 0.05). At 13 dpi, the TA2.75 group had significantly greater apparent ileal digestibility (AID) of dry matter (DM) and organic matter (OM) compared to the CC group. At 13 dpi, supplementation of TA linearly increased jejunal villus height (VH). Thus, this study showed that supplementation of TA at levels of 500 to 2750 mg/kg has the potential to be an anti-coccidial agent against E. maxima in broilers.